vengeful, wounding
There are damaging, spiteful, and wounding.
You could have detached, reserved, secluded, solitary, hardened, ruthless, obdurate, uncaring, spiteful, vengeful
Evitable is another 8 lettered word
to simplify.
disloyal
bacteria
renowned, esteemed
iniquity, disgrace
deviltry
Humorous.
ellipse
reunions, congress, assembly, conclave